XXY/etc are all variations within a sex. The above poster is correct to point out that sex is defined entirely by the gamete size that one's body is organized around producing in anisogamous species like humans, and is binary.

Intersex is a misleading term, the better term is https://en.wikipedia.org/wiki/Disorders_of_sex_development. There are male DSDs and female DSDs. Even in the case of ovotestes, you'll have one gamete produced, and the other tissue will be nonfunctional.